01 - In a large mixing bowl, whisk together olive oil, lemon juice, Greek yogurt, minced garlic, red wine vinegar, dried oregano, thyme, salt, black pepper, and lemon zest until fully combined.
02 - Add chicken cubes to the bowl and toss thoroughly to coat. Cover and refrigerate for a minimum of 1 hour and up to 8 hours for optimal flavor infusion.
03 - If using wooden skewers, submerge them in water for 30 minutes to prevent burning during grilling.
04 - Alternately thread marinated chicken, red onion, red and yellow bell peppers, and zucchini slices onto skewers, spacing pieces evenly for uniform grilling.
05 - Preheat grill or grill pan to medium-high heat and lightly oil the grates to prevent sticking.
06 - Place skewers on the grill and cook for 6 to 8 minutes per side, turning once, until chicken reaches 165°F internal temperature and develops grill marks.
07 - Transfer kabobs to a platter. Serve immediately with lemon wedges, sprinkle with fresh parsley, and accompany with tzatziki sauce if desired.